1. Field of the Invention
The present invention relates to a medical bag having excellent sanitariness, flexibility, transparency, and heat-resistance and suitable for use as a container of blood and various medicinal liquids.
2. Description of the Prior Art
Rigid containers made of, for example, glass, polyethylene, and polypropylene, and flexible (or non-rigid) bags made of, for example, poly(vinyl chloride) containing plasticizers have heretofore been known as medical containers or bags. However, the rigid containers have disadvantages in that air should be introduced into the containers by using a transfusion set provided with a vent needle or hole when the liquid contained therein is dropwise introduced into a human body through, for example, a vein and, therefore, the liquid contained therein is likely to be contaminated and air is liable to enter into the vein to cause air embolus. Thus, these rigid containers are not completely satisfied with the needs required from the sanitariness and dangerous viewpoints. On the other hand, flexible bags have advantages in that no air introduction is required, the bag itself is naturally compressed under an atmospheric pressure with the dropwise introduction of the liquid contained therein, no introduction of air contained in the bag into a human body occurs since the liquid contained therein remains in the bottom of the bags at the completion of transfusion, rapid transfusion can be carried out under pressure, and bags are not bulky unlike containers and, therefore, the transportation thereof is easy. For these reasons, the use of the flexible bags as medical containers or bags has increased. However, the use of these flexible bags, especially those made of non-rigid poly(vinyl chloride), involves possible problems caused by migration of the plasticizers into the liquid contained in the bags and toxicity of vinyl chloride monomer contained in poly(vinyl chloride).